A look at Japan's Damaged Nuclear Plants

Chicago Tribune- Officials ordered the evacuation to protect civilians in the event that radiation leaked from the plants. 'You want to err on the side of being cautious,' said (Ron) Chesser, director for the Center of Environmental Radiation Studies at Texas Tech University.

The situation at one of Japan's crippled nuclear power plants seemed to go from bad to worse as an explosion Saturday destroyed a building that houses one reactor and on Sunday another reactor began experiencing problems with its cooling system. An estimated 170,000 people who live within a 12-mile radius of the plant have been evacuated as a precaution in case the worst-case scenario occurs — a meltdown followed by the release of radioactive ash. An estimated 30,000 people have been evacuated within a six-mile radius of a nearby plant.

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Officials ordered the evacuation to protect civilians in the event that radiation leaked from the plants.

"You want to err on the side of being cautious," (Ron) Chesser said.